Striated Muscle Hamartoma in a Newborn

Abstract

Striated muscle hamartoma (SMH) is an uncommon benign lesion, that is usually congenital, polypoid, and primarily located on the head and neck. The key histopathologic sign is the existence of individualized fascicles of striated muscle affecting the dermis and subcutaneous fat tissue. Here we report the case of a newborn girl with an SMH, who presented with a congenital infiltrated plaque on her chin without any other associations.

Spontaneous Regression of a Plaque‐Type Striated Muscle Hamartoma

“…SMH is a rare, benign, congenital or acquired tumor that most frequently affects children . Clinically it is characterized by solitary or rarely multiple polypoid or nodular masses, with discrete or no changes in the color of the overlying skin and located predominantly on the head and neck .…”

“…Clinically it is characterized by solitary or rarely multiple polypoid or nodular masses, with discrete or no changes in the color of the overlying skin and located predominantly on the head and neck . Plaque‐type SMH has rarely been described . Histopathology demonstrates randomly arranged fascicles of mature striated muscle intermingled with mesenchymal, vascular, and neural elements throughout the dermis and hypodermis with immunohistochemical staining positive for desmin and Masson's trichrome (Fig.…”

“…Histopathology demonstrates randomly arranged fascicles of mature striated muscle intermingled with mesenchymal, vascular, and neural elements throughout the dermis and hypodermis with immunohistochemical staining positive for desmin and Masson's trichrome (Fig. ) . The etiology of SMH is unclear, although it has been suggested that an abnormality in the migration of embryonic mesodermal tissues may be involved .…”

“…In 2014 we reported a congenital case of SMH in a newborn girl, clinically characterized by a round, reddish‐orange plaque on the chin with no other associated anomalies (Fig. A).…”

“…Striated muscle hamartoma (SMH), or rhabdomyomatous mesenchymal hamartoma, is a rare, benign, congenital or acquired tumor . Surgical intervention is the therapeutic approach , but recent cases with recurrence after complete surgical excision and anecdotal spontaneous regressions have been documented in the medical literature .…”